Your probably using a free vpn account. Most free vpns don't hide relevant info. The paid vpn services are more strict about disclosure.

However, that said.
Unless the forum has something of yours (ugc) that you want removed. Move on. There's a ton of forums on the net.

If you truly want and must be a past of that particular forum... As stated by the previous poster. Talk to them, kiss their butt, apologize... send them pretty ecards. Candy sometimes works. Money definitely works.
And see if they'll let you back in.

Otherwise.. spin the Google search wheel and pick another forum. Make new friends. Or start your own forum...?